PhD defense by Selma Maric – University of Copenhagen

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28 February 2014

PhD defense by Selma Maric

PhD Defense

The Development of a stealth carrier system for structural studies of membrane proteins in solution

 

The project has been developed as a part of the crossdisciplinary Center for Synthetic Biology.

Time & Place
March 21st, 2014, 13:00 h

Festauditoriet, Bülowsvej 17, 1870 Frederiksberg

 

Supervisors
Professor Lise Arleth, Niels Bohr Institute, University of Copenhagen

Associate professor Thomas Günther-Pomorski, Department of Plant and Environmental Sciences, University of Copenhagen

Opponents
Professor Birger Lindberg Møller, Department of Plant and Environmental Sciences, University of Copenhagen (Chair)

Dr Giovanna Fragneto, Institut Laue-Langevin, Grenoble, France

Professor Tommy Nylander, Lund University, Lund, Sweden

 

Summary

Structural studies of membrane proteins remain a great experimental challenge. Functional reconstitution into artificial carriers that mimic the native bilayer environment allows for the handling of membrane proteins in solution and enables the use of small-angle scattering techniques for fast and reliable structural analysis. The difficulty with this approach is that the carrier discs contribute to the measured scattering intensity in a highly non-trivial fashion, making subsequent data analysis challenging. This work presents an elegant solution to circumvent the intrinsic complexity brought about by the presence of the carrier disc. In combination with small-angle neutron scattering (SANS) and the D2O/H2O-based solvent contrast variation method, it is demonstrated that it is possible to prepare specifically deuterated nanodisc carriers which become invisible to neutrons in 100% D2O at the length scales relevant to SANS (Figure 1). These “stealth” carrier discs may be used as a general platform for low-resolution structural studies of membrane proteins using well-established data analysis tools originally developed for soluble proteins.  


Figure 1. Schematic representation of the stealth nanodisc system in a buffer solution with a gradually increasing level of D2O (decreasing grayscale). From left to right: hydrogenated nanodisc consisting of a phospholipid bilayer (green) and membrane scaffold protein MSP (light blue), stealth nanodisc comprised of deuterated lipid and deuterated MSP at 60% D2O, stealth nanodisc at 80% D2O, stealth nanodisc at 100% D2O.